A Hardware Accelerated Relighting Engine for RenderMan

The goal of the system presented here is to allow a technical director to interactively adjust the lights in a frame. Since the time to render a cinematic quality frame can often span several hours, simply re-rendering the frame is far from ideal. Instead, a system like ours allows a technical director to view the frame with the current lighting parameters and then adjust, add or remove lights interactively. The display should update quickly enough to allow the technical director to interact with the tool in realtime. Updates to the scene may not be perfectly accurate, but should be close enough to allow the technical director to effectively set the mood for the frame. Once all the lights have been adjusted, the frame should be re-rendering fully at the maximum quality level.